FRICK QUANTUM CONTROL PANEL
OPERATION
S90-010 O
Page 48
CONTROL SETUP -
“SUCTION PRESSURE PULL DOWN” SCREEN
This screen is shown if the “Suction Pull Down” option was
selected in Panel Setup. This option is only valid when in
Suction Pressure Capacity Control. With this option enabled,
the Suction Pressure can be slowly lowered in steps from
the “Starting Suction Pressure” setpoint to the “Suction Pres-
sure Capacity Control” setpoint. Slowly “walking” the pres-
sure down prevents rapid drops in system pressure that
cause violent boiling of refrigerant in the system. When the
“Suction Pull Down” feature is activated and the compres-
sor is started, the Capacity Control setpoint is changed to
the current Suction Pressure. After the “Amount of Time”
setpoint has timed out, the Capacity Control setpoint is
changed again. The Capacity Control setpoint is reduced
by the amount of the “pressure band”. The system steps
down to this setpoint and stays there until the time-out pe-
riod has again elapsed. Then the Capacity Control setpoint
is reduced again. The Capacity Control setpoint changes
regardless of whether the system is following it or not. The
“Suction Pressure Pull Down” feature is reactivated every
time the machine is started unless it is deactivated.
This screen has the following setpoints:
Suction Pressure Reduction Step Pressure Band -
This is the amount of Suction Pressure that will be used
to step down the system. This value is subtracted from
the starting Suction Pressure to provide a Capacity
Control setpoint. The Capacity Control setpoint contin-
ues to be calculated by subtracting the pressure band
from the previously calculated Capacity Control set-
point until the Suction Pressure reading reaches the
operator entered Capacity Control setpoint.
Suction Pressure Reduction Step Amount of Time -
This is the time in minutes the Suction Pressure is main-
tained at each step during Suction Pressure pull down.
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